Forced air thermal energy storage system

ABSTRACT

A system including a chilled air generation system, a forced air convection system, one or more phase change material (PCM) modules, and a controller. The controller is configured to regulate the temperature of a facility by selectively utilizing the chilled air generation system and the forced air convection system based on multiple factors, which may include energy source type(s), relative costs of the energy from the source(s), availability of energy from the source(s), facility temperature, PCM module temperature, and/or temperature of goods stored within the facility, among other considerations. The controller may thus advantageously and cost-effectively control the periods of time during which the chilled air generation system is used and those during which the thermal energy stored in the PCM modules is used.

BRIEF DESCRIPTION OF DRAWINGS

Certain embodiments of the invention will be described with reference to the accompanying drawings. However, the accompanying drawings illustrate only certain aspects or implementations of the invention by way of example and are not meant to limit the scope of the claims.

FIG. 1 shows a diagram of a system in accordance with one or more embodiments of the invention.

FIG. 2A shows an isometric view of an example phase change material (PCM) module in accordance with one or more embodiments of the invention.

FIG. 2B shows an isometric view of a second example phase PCM module in accordance with one or more embodiments of the invention.

FIG. 3 shows an isometric view of a wall PCM module in accordance with one or more embodiments of the invention.

FIG. 4 shows an isometric view of a ceiling PCM module in accordance with one or more embodiments of the invention.

FIG. 5A shows an isometric view of a rack PCM module in accordance with one or more embodiments of the invention.

FIG. 5B shows a second isometric view of the rack PCM module in accordance with one or more embodiments of the invention.

FIG. 6 shows an isometric view of a forced air convection system in accordance with one or more embodiments of the invention.

FIG. 7A shows a first airflow diagram near a forced air convection system in accordance with one or more embodiments of the invention.

FIG. 7B shows a second airflow diagram near a forced air convection system in accordance with one or more embodiments of the invention.

FIG. 8A shows a flowchart of a first method of operating a forced air convection system controller in accordance with one or more embodiments of the invention.

FIG. 8B shows a flowchart of a second method of operating a forced air convection system controller in accordance with one or more embodiments of the invention.

FIG. 9 shows a flowchart of a method of operating a controller of a system in accordance with one or more embodiments of the invention.

FIG. 10 shows a flowchart of a method of operating a controller of a system in accordance with one or more embodiments of the invention.

FIG. 11 shows a diagram of a first example system in accordance with one or more embodiments of the invention.

FIG. 12 shows a diagram of a second example system in accordance with one or more embodiments of the invention.

FIG. 13 shows a diagram of a third example system in accordance with one or more embodiments of the invention.

DETAILED DESCRIPTION

Specific embodiments will now be described with reference to the accompanying figures. In the following description, numerous details are set forth as examples of the invention. It will be understood by those skilled in the art that one or more embodiments of the present invention may be practiced without these specific details and that numerous variations or modifications may be possible without departing from the scope of the invention. Certain details known to those of ordinary skill in the art are omitted to avoid obscuring the description.

In general, embodiments of the invention relate to devices, systems, and/or methods for temperature control. A system in accordance with one or more embodiments of the invention may include a chilled air generation system that provides chilled air. The chilled air may be provided to a facility for the storage of temperature sensitive goods. The facility may be, for example, a thermally insulated room of a building. Air, as used herein, refers to air or hypoxic air.

The system may also include one or more phase change material (PCM) modules disposed within the facility. The PCM modules may be mountable to a wall, ceiling, or other structure within the facility. The PCM modules may provide thermal energy storage that is used, in part, to regulate the temperature within the facility and/or the temperature of the goods disposed within the facility. The PCM modules may include a quantity of phase change material that has a solid to liquid phase transition temperature between

−60° Fahrenheit and 40° Fahrenheit. The PCM module may further include a sensor for measuring the temperature of the PCM or the PCM module. The temperature sensor may be a component of the PCM module or may be an external component linked to a controller by a communication link and thereby the controller may determine the temperature of the PCM or the PCM module based on information sent to the controller by the temperature sensor.

The PCM modules may be configured to be mounted, for example, to a wall of the facility, to a ceiling of the facility, to a floor of the facility, to a rack that is disposed within the facility, or to any other structure within the facility. For example, a PCM module may include a wall mounting flange that may be secured to the wall and thereby secure the PCM module to the wall.

The chilled air generation system, when active, may provide chilled air to the facility that causes the PCM modules to undergo a liquid to solid phase change. When the chilled air generation system is not active, a portion of the PCM within the PCM modules may undergo a solid to liquid phase change and thereby absorb heat. Absorbing heat may regulate the temperature of the facility at the solid to liquid phase change temperature while the chilled air generation system is not active.

The system may also include one or more forced air convection systems disposed within the facility. The forced air convection system may facilitate the regulation of the temperature of goods disposed near the forced air convection system and/or the temperature within the facility.

In one or more embodiments of the invention, the forced air convection system may include a reversible fan unit. The reversible fan module may be configured to generate a forced airflow in a first direction or a forced airflow in a second direction, which is opposite the first direction. The convective airflow generated by the reversible fan module may pass by one or more PCM modules within the facility and thereby exchange heat with the PCM modules.

Exchanging heat with the PCM modules may change the temperature of the airflow generated by the forced air convection system. The resulting temperature changed airflow may be used to regulate the temperature of goods disposed in the facility. For example, the forced air convection system may generate an airflow that causes warm ambient air to pass by PCM modules that have a temperature lower than the temperature of the warm ambient air. The airflow generated may exchange heat with the PCM modules and thereby reduce the temperature of the airflow to a lower temperature. The reduced temperature airflow may be directed towards goods in the facility and thereby cool the goods or via mixing may maintain the environment within the facility at or near a desired temperature or temperature range, thereby maintaining the desired temperature of the goods.

In one or more embodiments of the invention, the airflow generated by the forced air convection system may also interact with the PCM modules and therein cause heat exchange between the airflow and the PCM modules. The aforementioned heat exchange may also cool the nearby goods.

The system may also include a controller that is operably connected to the chilled air generation system and the forced air convection system. The controller may be configured to control the generation of chilled air by the chilled air generation system and the operation of the forced air convection system. The controller may activate the chilled air generation system and the forced air convection system selectively to regulate the temperature of the facility and/or goods disposed within the facility. The controller may also be configured to minimize the use of energy and/or cost of the use of energy needed to regulate the temperature of the facility and/or the goods disposed within the facility.

The system may also include a power distributor that is operably connected to the controller. The power distributor may control the supply of power to the chilled air generation system and/or the forced air convection system. The power distributor may be connected to one or more power sources. When multiple power sources are available, the power sources may include, for example, a first power source that is an on-demand power source and a second power source that is a renewable power source. The power distributor may be configured to supply power from the renewable power source when such power is available and to supply power from the on-demand power source when power from the renewable power source is not available. The operation of the power distributor may be specified by the controller by way of sending a command through the operable connection.

The controller may also be configured for temporally shifting power use or peak power usage. For example, an on-demand power source may have a higher cost during the daytime, such as during normal business hours or when residential usage may be highest. Likewise, a solar power source may be available only during the day, and wind power may only be available when winds are sufficient to produce power. The PCM modules may provide for temperature regulation within the facility during peak power cost times and/or during low power availability times, and the controller(s) may be configured to operate the chilled air generation system when power is available and/or low cost. The system and controller may thus account for numerous factors to determine when to operate the chilled air generation system and when to operate based on the thermal energy storage of the PCM modules. In some embodiments, these periods of time may also coincide with times when the chilled air generation system may operate at higher efficiency.

A method of operating systems disclosed herein may include, for example, utilizing the renewable power source during a first time period, when such power is available, to operate the chilled air generation system. Operation of the chilled air generation system may cause the PCM modules to undergo a liquid to solid phase change. The method may also include deactivating the chilled air generation system during a second period of time when power from the renewable power source is unavailable. During the second time period, the fans of the forced air convection system may operate, continuously or intermittently, and thereby generate convection currents within the facility. The convection currents may cause heat transfer to the PCM modules which is absorbed by way of a solid to liquid phase change of a portion of the PCM modules. Absorption of the heat may regulate the temperature of the facility and/or the temperature of goods disposed within the facility.

FIG. 1 shows a diagram of a system in accordance with one or more embodiments of the invention. The system may regulate the temperature of goods and/or the temperature of a facility in which the goods are disposed. The system includes a facility (100), a chilled air generation system (120), one or more PCM modules (130, 131, 132), and a controller (160). Additionally, where two or more power sources are available, the system may include a power distributor (150). The facility, as noted above, included means to circulate air within the facility, and the circulation may be provided by a fan of the chilled air generation system, for example, or may be provided via a separate forced air convection system (140). Each of the components of the system is described below.

The system may include a facility (100). The facility may be a physical structure. Goods (110) may be stored within the facility. For example, goods (110) may be disposed on racks (115) within the facility. The goods (100) may be temperature sensitive and may spoil or otherwise become less valuable when exposed to temperatures that fall outside of a predetermined range.

In one or more embodiments of the invention, the facility (100) may be a building. The building may be insulated. For example, the building may be a static structure that includes insulated walls.

In one or more embodiments of the invention, the facility (100) may be a room of a building. The room may be insulated, e.g., at least a portion of the walls, roof, and/or floor of the room may be thermally insulated from a surrounding environment. For example, the room may be a walk in freezer or refrigerator.

In one or more embodiments of the invention, the facility (100) may be an enclosure. The enclosure may be, for example, a train car, a shipping container, a storage container, a frozen/refrigerated goods shipping vehicle, or any other moveable structure that may store goods. The enclosure may be a refrigerated transport vehicle or a refrigerated box car of a train. In one or more embodiments of the invention, the refrigerated box car may include an insulated portion, a chilled air supply that supplies chilled air to the insulated portion, a PCM module disposed within the insulated portion, and/or a forced air convection system disposed within the insulated portion. The vehicle may be any type of vehicle including, but not limited to, an automobile, train car, boat, or aircraft.

The system may include a chilled air generation system (120). The chilled air generation system (120) may be a physical structure that produces chilled air. The chilled air generation system (120) may include an air return (121) that receives air from the facility (100) and a chilled air feed (122) that supplies chilled air to the facility (100). The chilled air generation system (120) may be any type of air conditioning system and may include condenser coils, defrost unit, and thermostats, among other components.

The chilled air generation system (120) may be connected to the controller (160) by an operable connection. The chilled air generation system (120) may receive commands from the controller (160) by way of the operable connection and thereby perform action under the direction of the controller. For example, various sensors may send temperature measurements to the controller. For example, one or more temperature sensors measuring a temperature of the air within the facility, a temperature of the PCM or PCM module, and/or a temperature of the good may be monitored by the controller. By way of the operable connection, the controller may send a command to the chilled air generation system to generate chilled air based on one or more of the temperature measurements.

The system may further include one or more PCM modules (130, 131, 132). The PCM modules (130, 131, 132) may be physical structures. The PCM modules (130, 131, 132) may facilitate the regulation of the temperature of the goods disposed within the facility and/or the temperature of the facility. The PCM modules (130, 131, 132) may include a volume of phase change material that has a solid to liquid phase transition temperature or temperature range. The phase change materials) used and the associated solid to liquid phase transition temperature may be selected, for example, based on a regulation temperature of the goods disposed within the facility and/or the regulation temperature of the facility.

Each of the PCM modules (130, 131, 132) may include one or more housings and each housing may include one or more phase change material reception ports. The housings may be made of, for example, a plastic, such as high density polyethylene, or any other appropriate material that may provide the desired compatibility with the phase change material and the requisite heat transfer characteristics. The shape of the housings may be, for example, cylindrical, rectangular, or in the form of a panel. In one or more embodiments of the invention, the housings may have a shape that maximizes heat exchange between the PCM module and airflow proximate the PCM module (130, 131, 132). The housings may have other shapes without departing from the invention.

The phase change material reception ports may be closable orifices for receiving a phase change material and thereby enabling a quantity of phase change material to be disposed within the housings. The housings may be configured to contain, for example, up to 1 gallon of phase change material. The phase change material may have a solid-liquid phase change temperature or temperature range based on a desired regulation temperature of goods. In one or more embodiments of the invention, the solid-liquid phase change temperature is between −60° and 40° Fahrenheit, such as between −20° and 40° Fahrenheit, or between 0° and about 30° Fahrenheit.

The quantity and/or type of phase change material may be set based on the desired regulation temperature of the goods. In one or more embodiments of the invention, the phase change material may include water and a quantity of one or more salts. The concentration of the one or more salts may be set, at least in part, on a desired temperature profile of the goods. In one or more embodiments of the invention, the regulation temperature of the goods is between −60° Fahrenheit and 50° Fahrenheit.

In one or more embodiments of the invention, a PCM module may be configured to be mounted to a structure. FIG. 2A shows an example of a PCM module (250) in accordance with embodiments of the invention that is configured to mount to a structure. More specifically, FIG. 2A shows an isometric view of an example of a PCM module (250) in accordance with one or more embodiments of the invention. As seen from FIG. 2A, the PCM module (250) includes a number of housings (255) for holding phase change material. While not shown, each housing (255) may include one or more orifices that enable phase change material to be added or removed from an internal volume of the housing.

Each of the housings may be disposed on a support structure (260). The support structure (260) may mechanically connect each of the housings (255). In one or more embodiments of the invention, the support structure (260) may include one or more rails. The rails may be, for example, structural pipe, plastic pipe, or metal pipe. The rails may pass through each of the housings (255), or may individually attach two housings (255) to collectively form a unit. In one or more embodiments of the invention, the support structure (260) may include one or more cross members that improve the stiffness of the support structure (260). In one or more embodiments of the invention, the support structure may be configured to mechanically attach to the facility or to a structure within the facility, and in some embodiments may be configured to attach to the housing of the forced air convection system (140) (FIG. 1).

In one or more embodiments of the invention, the support structure (260) may spatially separate each of the housings (255) and thereby create airflow paths. The airflow paths may increase convective heat exchange between the PCM module (250) and an airflow proximate the PCM module (250). The support structure (260) may include one or more spacers (265) disposed on the rails and between adjacent housings (255). The spacers may be, for example, sections of plastic pipe or metal pipe having an inner diameter that is larger than the outer diameter of each rail.

While the example PCM module shown in FIG. 2A includes four housings, the shape, size, quantity, and orientation of the housings may be varied without departing from the scope of the invention.

For example, FIG. 2B shows an isometric view of a second example of a PCM module (270) in accordance with one or more embodiments of the invention. As seen from FIG. 2B, the PCM module (270) includes a number of housings (275) for holding phase change material. In comparison to the housings (255, FIG. 2A) of the example PCM module (250, FIG. 2A), the housings (275) of the second example PCM module (270) are thinner and a greater number of plastic housings (275) are disposed on the support structure. Thus, the size, number, and spacing of the plastic housings (275) may be modified without departing from the invention.

Returning to FIG. 1, the example PCM module shown in FIGS. 2A and/or 2B may be configured to mount: to a ceiling of the facility, e.g., a ceiling PCM module (130); to a wall of the facility, e.g., a wall PCM module (131); and/or to a rack or other structure disposed within the facility (100), e.g., rack PCM module (132).

FIG. 3 shows a wall PCM module (131) in accordance with one or more embodiments of the invention. The wall PCM module (131) may include like parts as those of the example PCM module shown in FIG. 2A. The wall PCM module (131) may also include one or more wall mounting brackets (310). The wall mounting brackets (310) may be physical structures that are configured to attach the wall PCM module (131) to a wall (310) of the facility. For example, the wall mounting brackets may include a wall flange and a section of pipe that spaces the wall PCM module (131) a fixed distance from the wall (300) when attached to the wall (300) by the wall mounting brackets (310).

While the wall mounting brackets in FIG. 3 are illustrated as being a set of four and extending at a right angle from the wall PCM module (131), the number of wall mounting brackets (310), mounting location, and orientation may be varied without departing from the invention.

FIG. 4 shows a ceiling PCM module (130) in accordance with one or more embodiments of the invention. The ceiling PCM module (130) may include like parts as those of the example PCM module shown in FIG. 2A. The ceiling PCM module (130) may also include one or more ceiling mounting brackets (400). The ceiling mounting brackets (400) may be physical structures that are configured to attach the ceiling PCM module (130) to a ceiling (not shown) of the facility. For example, the ceiling mounting brackets (400) may include a ceiling flange (405) and a section of pipe (410) that spaces the ceiling PCM module (130) a fixed distance from the ceiling when attached to the ceiling by the ceiling mounting brackets (400).

While the ceiling mounting brackets in FIG. 4 are illustrated as being a set of two and extending at a right angle from the ceiling PCM module (130), the number of ceiling mounting brackets (400), mounting locations, and mounting orientation may be varied without departing from the invention.

FIG. 5A shows a first view of a rack PCM module (132) in accordance with one or more embodiments of the invention. In FIG. 5A, a grating of the rack PCM module (132) is not shown. In FIG. 5B, the gating of the rack PCM module (132) is shown.

The rack PCM module (132) may include like parts as those of the example PCM module shown in FIG. 2A. The rack PCM module (132) may also include one or more rack mounting rails (500). The rack mounting rails (500) may be physical structures that are configured to attach the rack PCM module (132) to a rack that is disposed within a facility, e.g., a portion of a structure within the facility. For example, the rack mounting rails (500) may include one or more adapters (505) that mount the rack PCM module (132) to the rack mounting rails (500). The rack mounting rails (500) may, in turn, be mounted to a rack.

While the rack mounting rails (500) in FIG. 5A are illustrated as being a set of two and extending along a depth of the rack PCM module (132), the number of rack mounting rails (500), mounting locations, and mounting orientation may be varied without departing from the invention.

FIG. 5B shows a second view of the rack PCM module (132) in accordance with one or more embodiments of the invention. As seen from FIG. 5B, the rack PCM module (132) may include a platform (510). In one or more embodiments of the invention, goods may be disposed on the platform (510).

The platform (510) may be a physical structure. In one or more embodiments of the invention, the platform (510) may be a wire frame structure that enables an airflow through the platform (510). By allowing airflow through the platform (510), thermal exchange between the PCM modules of the rack PCM module (132) may be greater than thermal exchange between the PCM modules of the rack PCM module (132) in proximity to a platform (510) that does not enable airflow through the platform (510).

Returning to FIG. 1, the system may include one or more forced air convection systems (140). FIG. 6 shows a diagram of a forced air convection system in accordance with one or more embodiments of the invention. The forced air convection system may include a pallet (600), a housing (610), optionally one or more integrated PCM modules (620), a reversible fan module (630), a battery backup (640), and a forced air convection system controller (650). Each component of the forced air convection system is described below.

The forced air convection system may include a pallet (600). The pallet (600) may be a structural member that is a base for other components of the forced air convection system. The pallet (600) may be, for example, a wood or metal structure configured to support the weight of the other components of the forced air convection system and to enable the forced air convection system to be easily moved from one location to another location. The pallet (600) may include a number of airflow channels (605) through which air may flow and thereby enable air to flow through the pallet (600). While the pallet (600) is shown as including five narrow slots as airflow channels (605) in FIG. 1A, one of ordinary skill in the art will appreciate that the airflow channels (605) may have other shapes or configurations without departing from the invention. The flow of air near the pallet is further described with respect to FIGS. 7A-7B.

The forced air convection system may include a housing (610). The housing (610) may include an airflow path from the pallet (600) to the reversible fan module (630). A first end of the airflow path may be disposed proximate the pallet (600) and the second end of the airflow path may be disposed proximate the reversible fan module (630). The flow of air through the housing is further described with respect to FIGS. 7A-7B.

The housing (610) may be made of a structural material such as metal. In one or more embodiments of the invention, the metal may be aluminum. The housing (610) may be disposed on the pallet and support the reversible fan module (630). While the housing (610) is depicted as a tubular structure having a rectangular cross section in FIG. 6, one of ordinary skill in the art will appreciate that the housing (610) may have other shapes or configurations without departing from the invention.

The forced air convection system may optionally include one or more integrated PCM modules (620). Each of the integrated PCM modules (620) may include one or more housings and each housing may include one or more phase change material reception pods. The housings may be made of, for example, high density polyethylene. The shape of the housings may be, for example, cylindrical, rectangular, or in the form of a panel. In one or more embodiments of the invention, the housings may have a shape that maximizes heat exchange between the PCM module and airflow proximate the PCM module. In one or more embodiments of the invention, the airflow is generated by the fan module (630). The housings may have other shapes without departing from the invention.

The phase change material reception ports may be closable orifices for receiving a phase change material and thereby enabling a quantity of phase change material to be disposed within the housings. The housings may include, for example, up to 1 gallon of phase change material. The phase change material used may include a solid-liquid phase change temperature set based on a desired regulation temperature of goods. In one or more embodiments of the invention, the solid-liquid phase change temperature is between −60° and 40° Fahrenheit.

The quantity and/or type of phase change material may be set based on the desired regulation temperature of the goods, as well as the configuration and location of the facility. In one or more embodiments of the invention, the phase change material may include water and a quantity of one or more salts. The concentration of the one or more salts may be set, at least in part, on a desired temperature profile of the goods. In one or more embodiments of the invention, the regulation temperature of the goods is between −20° Fahrenheit and 38° Fahrenheit.

In one or more embodiments of the invention, the integrated PCM modules (620) of the forced air convection system may the same as the PCM module shown in FIG. 2A, and include similar variations.

Returning to FIG. 6, the forced air convection system may include a reversible fan module (630). The reversible fan module (630) may be configured to generate an airflow through the housing (610) and/or within the facility, and thereby cause heat exchange between the airflow and the PCM modules. The reversible fan module (630) may include one or more fans (631) disposed on a support structure (632). In one or more embodiments of the invention, the reversible fan module (630) includes four fans.

The one or more fans (631) may be electrically driven fans. In one or more embodiments of the invention, the fans (631) may be high efficiency fans and draw 4 watts or less of power, each.

The fans (631) may be reversible and thereby generate a forward or reverse airflow throughout the housing (610). Each of the fans (631) may be controlled by a controller, e.g., the controller may instruct the fans (631) to operate in a forward direction, a reverse direction, or to not operate.

The fans (631) may be disposed on a support structure (632). The support structure (632) may be a mechanical structure that orients and positions the fans (631) and thereby directs airflow generated by the fans (631). The support structure (632) may be, for example, an aluminum frame. While the support structure (630) is illustrated as a pyramidal structure in FIG. 6, the support structure (630) may have other shapes without departing from the invention.

The forced air convection system may include a battery backup (640). The battery backup (640) may include a battery and a regulator. The regulator may be configured to charge the battery when power from the power distributor (150) is available and to supply power to the reversible fan module (630) and/or controller (650) when power from the power distributor (150) is not available.

The forced air convection system may include a controller (650). The controller (650) may be configured to operate the fans (631) of the reversible fan module (630). The controller (650) may be further configured to monitor the temperature of goods, phase change material, and/or the facility, and activate the fans (631) in response to the monitored temperature exceeding a predetermined range and/or value.

The controller (650) may be a computing device such as a computer, embedded system, microcontroller, or any other type of computing device. The controller (650) may include a processor, memory, communication unit, and a non-transitory storage medium on which instructions are stored that when executed by the processor cause the controller to perform the functions shown in FIGS. 8A and 8B.

The processor may be, for example, a central processing unit. The memory may be, for example, random access memory or persistent memory. The communication unit may be a network adapter that allows the controller (650) to communicate with other devices such as a temperature regulation system. The temperature regulation system may be, for example, a heating, ventilation, and air conditioning (HVAC) system, a refrigeration system, or a freezer system. The non-transitory computer readable medium may be a CD, DVD, storage device, a diskette, a tape, flash memory, physical memory, or any other computer readable storage medium.

The forced air convection system (140) may be connected to the controller (160) by way of an operable connection and take action based on commands received from the controller (160). in some embodiments, the forced air convection system (140) may also include a controller (650), which may be part of an overall control system and may be subservient to the controller (160).

Returning to FIG. 1, the system may include a power distributor (150). The power distributor (150) may be a power distribution device configured to supply power to the chilled air generation system (120) and the one or more forced air convection systems (140). The power distributor (150) may be a physical device including one or more electric circuits that enable the power to be distributed. For example, the power distributor (150) may include one or more relays, one or more high power transistors, and/or digital control circuitry for controlling the relays and/or high power transistors.

The power distributor (150) may be configured to receive power from one or more power sources, such as an on-demand power source (151) and a renewable power source (152). The power distributor (150) may be further configured to selectively supply power based on commands received from the controller (160) by way of an operable connection. For example, during a first time period the controller (160) may send a command to the power distributor (150) indicating that power from the renewable power source (152) should be supplied. During a second period of time, the controller (160) may send a command to the power distributor (150) indicating that power from the on-demand power source (151) should be supplied. Based on the commands, the power distributor (150) may supply power from the renewable power source (152) during the first period and may supply power from the on-demand power source (151) during the second period.

In one or more embodiments of the invention, the renewable power source (152) may generate power by receiving light. For example, the renewable power source (152) may include a photovoltaic cell or a photo-thermalelectric system. The renewable power source (152) may produce power intermittently when ambient conditions allow, e.g., when there is sufficient light to produce power or power production being proportional to ambient light intensity.

In one or more embodiments of the invention, the renewable power source (152) may generate power by receiving wind. For example, the renewable power source (152) may include a wind turbine. The renewable power source (152) may produce power intermittently when ambient conditions allow, e.g., when there is sufficient wind to produce power or power production being proportional to wind speed.

In one or more embodiments of the invention, the on-demand power source (151) may generate power by consuming a fuel source, e.g., coal, natural gas, nuclear, oil, stored water, etc. For example, the on-demand power source (151) may include a coal fired steam generator coupled to a turbine. The on-demand power source (151) may produce power on-demand and as needed, e.g., a base load power supply.

The system may include the controller (160). The controller (160) may be a computing device such as a computer, embedded system, microcontroller, or any other type of computing device. The controller (160) may include a processor, memory, communication unit, and a non-transitory computer readable medium on which instructions are stored that when executed by the processor cause the controller to perform the functions shown in FIGS. 9 and 10.

The processor may be, for example, a central processing unit. The memory may be, for example, random access memory or persistent memory. The communication unit may be a network adapter that allows the controller to communicate with other devices including the forced air convection system (140) and/or the chilled air generation system (120) by way of operable connections. The non-transitory computer readable storage medium may be a CD, DVD, storage device, a diskette, a tape, flash memory, physical memory, or any other computer readable storage medium.

FIG. 8A shows a flowchart in accordance with one or more embodiments of the invention. The method depicted in FIG. 8A may be used to operate a forced air convection system controller in accordance with one or more embodiments of the invention. One or more steps shown in FIG. 8A may be omitted, repeated, and/or performed in a different order among different embodiments.

In Step 800, forced air convection system obtains a command to activate a reversible fan module. The command may be received from a controller. The command may include a direction, rotation rate, duty cycle, and/or other parameter that specifies a modification of the operation of the reversible fan module. In one or more embodiments of the invention, the command may be sent to the forced air convection system via a wired or wireless connection. For example, the wired or wireless connection may be a direct wired/wireless connection, e.g., an IEEE 802.15.1 standard connection, or a network wired/wireless connection, e.g., an IEEE 802.11 standard connection. A network wired or wireless connection may support Internet Protocol (IP) communications. The wired or wireless connection may support other communication protocols without departing from the invention.

In Step 810, the system activates the reversible fan module based on the received command, and may activate the reversible fan module by setting a direction and/or rate of power to one or more fans of the reversible fan module.

FIGS. 7A and 7B show examples of airflows generated by the one or more fans (131) when power is supplied to the one or more fans (131). In general, the desired direction of airflow generated by the fans may be based on a relative temperature of the air within the facility as compared to the temperature of the PCM modules, among other factors. In the embodiments of FIGS. 7A and 7B, the forced air convection system is illustrated as including the optional integral PCM modules. Specifically, FIG. 7A shows airflow, illustrated by arrows with wavy tails, generated by the one or more fans (131) when the fans are operated in a first direction and FIG. 7B shows airflow generated by the one or more fans (131) when the fans are operated in a second direction. As seen from the illustrations, the airflow throughout the forced air convection system may be reversed by operating the one or more fans (131) in a first or second direction and thereby the controller may control the flow of air within the forced air convection system and/or within the facility by operating the one or more fans (131).

Additionally, when operated in the first direction as shown in FIG. 7A, the forced air convection system may draw ambient air into the housing by way of the fans, pass the ambient air near the PCM modules and thereby cause heat exchange between the PCM modules and the ambient air, and exhaust the air out of the housing through the pallet. In contrast, when operated in the second direction as shown in FIG. 7B, the forced air convection system may draw ambient air into the housing by way of the pallet, pass the ambient air near the PCM modules and thereby cause heat exchange between the PCM modules and the ambient air, and exhaust the air out of the housing through the fans. Depending on the temperatures of the PCM modules and the air, heat may flow from the PCM modules and into the ambient air or from the ambient air and into the PCM modules.

FIG. 8B shows a flowchart in accordance with one or more embodiments of the invention. The method depicted in FIG. 8B may be used to operate a controller in accordance with one or more embodiments of the invention. One or more steps shown in FIG. 8B may be omitted, repeated, and/or performed in a different order among different embodiments.

In Step 850, a controller determines an ambient temperature. The controller may determine the ambient temperature based on a temperature sensor linked to the controller. The temperature sensor may be a component of the forced air convection system or may be an external component linked to the controller by a communication link and thereby the controller may determine the ambient temperature based on information sent to the controller by the temperature sensor.

In Step 860, the controller activates a reversible fan module in response to the ambient temperature exceeding a predetermined temperature. The controller may activate the reversible fan module by setting a direction and/or rate of power to one or more fans of the reversible fan module, Activating the reversible fan module may cause an airflow, as shown in FIGS. 7A and/or 7B, which causes heat to be exchanged with a PCM module. The exchange of heat may cool the airflow and thereby cool goods disposed and/or regulate the temperature of a facility in which the goods are stored.

The ambient temperature could exceed a predetermined temperature for any reason including a failure of a component, a temporary power outage that renders the chilled air generation system inoperable, or any other reason.

In one or more embodiments of the invention, the predetermined temperature may be a temperature that extends the shelf life of goods. For example, if the goods are frozen goods, the predetermined temperature may be 27° Fahrenheit. In a second example, if the goods are produce, the predetermined temperature may be 40° Fahrenheit.

In Step 870, the controller deactivates the reversible fan module of the forced air convection system in response to the ambient temperature falling below the predetermined temperature. The method ends following Step 870.

FIG. 9 shows a flowchart in accordance with one or more embodiments of the invention. The method depicted in FIG. 9 may be used to operate a controller in accordance with one or more embodiments of the invention. One or more steps shown in FIG. 9 may be omitted, repeated, and/or performed in a different order among different embodiments.

In Step 900, a controller may obtain a first period of time having a high electricity cost and a second period of time having a low electricity cost. The controller may be operably linked to a power distributor, one or more forced air convection systems, and a chilled air generation system. As the system may require a higher energy demand during a time period when the chilled air generation system is running, the controller may optimize the time(s) that the chilled air convection system is operating. For example, during peak energy cost times, and/or when less costly (lower relative cost), renewable energy sources are not available, the controller may be configured to selectively run the forced air convection system. The system will thus be utilizing the thermal energy storage of the PCM module instead of operating the chilled air generation system. In this manner, the controller may work to reduce energy demands and decouple the system from constant, on-demand energy sources, resulting in a cost savings in overall energy requirements.

In Step 910, the controller supplies power generated by a renewable source during the first period of time. The controller may supply the power by sending a command to the power distributor. The power distributor may be configured to receive power from an on-demand source and a renewable source. The command may indicate that the power distributor is to provide power from the renewable source to the one or more forced air convection systems and the chilled air generation system. The command may be sent at the start of the first time period. In response to the first command, the power distributor may transmit power received from the renewable source to the one or more forced air convection systems and/or the chilled air generation system.

In Step 920, the controller supplies power generated by the on-demand source during the second time period. The controller may supply the power by sending a second command to the power distributor. The command may indicate that the power distributor is to provide power from the on-demand source to the one or more forced air convection systems and the chilled air generation system. The command may be sent at the start of the second time period. In response to the second command, the power distributor may transmit power received from the on-demand source to the one or more forced air convection systems and/or the chilled air generation system.

FIG. 10 shows a flowchart in accordance with one or more embodiments of the invention. The method depicted in FIG. 10 may be used to operate a controller in accordance with one or more embodiments of the invention. One or more steps shown in FIG. 10 may be omitted, repeated, and/or performed in a different order among different embodiments.

In Step 1000, a controller may obtain a first period of time having a high electricity cost and a second period of time having a low electricity cost. The controller may be operably linked to a power distributor, one or more forced air convection systems, and a chilled air generation system. As the system may require a higher energy demand when the chilled air generation system is running, the controller may be configured to minimize energy usage during the first period of time. For example, during peak energy cost times, or when cheap, renewable energy sources are not available, the controller may selectively run the forced air convection system, during the second period of time, utilizing the thermal energy storage of the PCM module instead of operating the chilled air generation system for the first period of time. In this manner, the controller may work to reduce energy demands and decouple the system from constant, on-demand energy sources, resulting in a cost savings in overall energy requirements.

In Step 1010, the controller supplies power generated to the one or more forced air convection systems and the chilled air generation system during the first period of time. In one or more embodiments of the invention, supplying power during the first time period causes the chilled air generation source to generate a chilled airflow throughout a facility, where the chilled airflow has a temperature below a solid-liquid phase change transition temperature of one or more PCM modules within the facility. Exposing the PCM modules to the chilled air may cause at least a portion of the phase change material within the phase change material modules to undergo a liquid to solid phase transition. The PCM modules may be wall PCM modules, ceiling PCM modules, or rack PCM modules, for example.

In Step 1020, the controller terminates the supply of power to the one or more forced air convection systems and/or the chilled air generation source during the second time period. Terminating the supply of power may terminate the generation of chilled air by the chilled air generation system. While the chilled air is not supplied to the facility by the chilled air generation source, the temperature within the facility may begin to rise. When the temperature reaches a predetermined temperature, the forced air convection system may activate and thereby cause convective airflow within the facility. When the temperate reaches the solid to liquid phase transition temperature, portions of the phase change material within the PCM modules may undergo a solid to liquid phase change and thereby absorb heat. Absorbing heat by the PCM modules may regulate the temperature of the facility and thereby the temperature of goods disposed within the facility. The convective currents generated by the forced air convection system may ensure uniformity of temperature within the facility by way of convective thermal exchange.

Thus, the method shown in FIG. 10 may decrease the cost of regulating the temperature of goods by shifting the use of electricity to periods of time when the cost is low and utilizing PCM modules to regulate the temperature of goods during periods of time when the cost of energy is high.

In a like manner, a controller may also be configured to regulate the temperature of goods by shifting the use of electricity to periods of time when a renewable energy source is available, and utilizing PCM modules to regulate the temperature of goods during periods of time when the renewable energy source is unavailable.

The following are examples of systems in accordance with one or more embodiments of the invention. The following examples are explanatory examples and not intended to the limit the invention.

Example 1

FIG. 11 shows an example system in accordance with embodiments of the invention. The system includes a facility (100), a chilled air generation system (120), and a forced air convection system (140). The chilled air generation system (120) and the forced air convection system (140) may be configured to operate based on temperature measurements of the interior of the facility (100) or goods. More specifically, the chilled air generation system (120) may be configured to generate chilled air when the temperature measurement of the interior of the facility (100) or goods indicates that the measured temperature is above a predetermined value.

The forced air convection system (140) may be configured to operate one or more reversible fan modules (140) in a first direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is above a second predetermined value. The forced air convection system (140) may be further configured to operate the reversible fan modules in a second direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is below a second predetermined value.

The first predetermined value may be less than the second predetermined value.

Example 2

FIG. 12 shows an example system in accordance with embodiments of the invention. The system includes a facility (100), a chilled air generation system (120), and a first forced air convection system (1200) and a second forced air convection system (1201). The chilled air generation system (120), the first forced air convection system (1200), and the second forced air convection system (1201) may be configured to operate based on temperature measurements of the interior of the facility (100). More specifically, the chilled air generation system (120) may be configured to generate chilled air when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is above a predetermined value.

Both forced air convection systems (1200, 1201) may be configured to operate reversible fan modules in a first direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is above a second predetermined value. The forced air convection systems (1200, 1201) may be further configured to operate the reversible fan modules in a second direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is below a second predetermined value.

The first predetermined value may be less than the second predetermined value.

Example 3

FIG. 13 shows an example system in accordance with embodiments of the invention. The system includes a facility (100), a chilled air generation system (120), a first forced air convection system (1200), a second forced air convection system (1201), and multiple PCM modules (1300, 1301, 1302, 1303, 1304, 1305). The chilled air generation system (120), the first forced air convection system (1200), the second forced air convection system (1201), and the multiple PCM modules (1300, 1301, 1302, 1303, 1304, 1305) may be configured to operate based on temperature measurements of the interior of the facility (100), or of the PCM modules. More specifically, the chilled air generation system (120) may be configured to generate chilled air when the temperature measurement of the interior of the facility (100), or PCM modules, indicates that the measured temperature is above a predetermined value.

Both forced air convection systems (1200, 1201) may be configured to operate reversible fan modules in a first direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is above a second predetermined value. The forced air convection systems (1200, 1201) may be further configured to operate the reversible fan modules in a second direction when the temperature measurement of the interior of the facility (100) indicates that the measured temperature is below a second predetermined value.

The PCM modules (1300, 1301, 1302, 1303, 1304, 1305) may be configured to absorb heat when exposed to a temperature that is above the second predetermined value. The PCM modules (1300, 1301, 1302, 1303, 1304, 1305) may be further configured to release heat when exposed to a temperature that is below the second predetermined value. The first predetermined value may be less than the second predetermined value.

One or more embodiments of the invention may provide one or more of the following advantages: i) a system in accordance with embodiments of the invention may regulate a temperature of a good and/or a facility in which a good is stored, ii) the system may reduce the cost of regulating the temperature of goods by maintaining the temperature of goods using the PCM modules to regulate temperature during periods of time where the cost of energy is high, e.g., reduce the cost by 25-50% by selectively not using chilled air generation systems during time periods when on-demand energy is more costly or unavailable, iii) the system in accordance with embodiments of the invention may regulate a temperature of a good to a desired range for a desired period of time, for example, of four to eight hours, iv) the system in accordance with embodiments of the invention may be configurable to maintain the temperature of goods to a predetermined temperature between −60° and 40° Fahrenheit, v) the system in accordance with embodiments of the invention may be reusable, e.g., no component is used up or otherwise lost during use, vi) the system may be configurable to regulate the temperature of a facility of arbitrary size, and vii) one or more embodiments of the invention may enable an existing facility to be retrofitted by one or more embodiments herein.

As used herein, “time” and “period of time” may refer to operational phases when certain conditions are met, and may not necessarily refer to discrete blocks of time, such as 15 minutes or 30 minutes. One of ordinary skill in the art, with the benefit of the disclosure herein, would appreciate that a first period of time and a second period of time may be alternately utilized as necessary by the controller and not on a fixed schedule.

While the invention has been described above with respect to a limited number of embodiments, those skilled in the art, having the benefit of this disclosure, will appreciate that other embodiments can be devised which do not depart from the scope of the invention as disclosed herein. Accordingly, the scope of the invention should be limited only by the attached claims. 

What is claimed is:
 1. A system, comprising: a forced air convection system configured to: provide a chilled airflow from a chilled air generation system during a first period of time; and generate a convective airflow during a second period of time; one or more phase change material (PCM) modules for thermal energy storage, each comprising a phase change material, wherein the PCM module(s) is(are) configured to exchange heat with the convective airflow and the chilled airflow; and a controller configured to determine the second period of time based, at least in part, on the first period of time.
 2. The system of claim 1, wherein the PCM module(s) is(are) configured to be mounted to a ceiling of a facility, a wall of a facility, or a rack of a facility, respectively.
 3. The system of claim 1, wherein the PCM module is configured to be mounted to a rack of a facility, wherein the rack is structure on which goods may be disposed.
 4. The system of claim 3, wherein the forced air convection system is disposed at a higher elevation than the PCM module on the rack.
 5. The system of claim I, wherein the PCM has a solid to liquid phase transition temperature or temperature range such that heat exchange between the convective airflow and the PCM module causes a portion of the phase change material of the PCM module to undergo a solid to liquid phase transition.
 6. The system of claim 1, wherein the PCM has a liquid to solid phase transition temperature or temperature range such that heat exchange between the chilled airflow and the PCM module causes a portion of the phase change material of the PCM module to undergo a liquid to solid phase transition.
 7. The system of claim 6, wherein the convective airflow and the chilled airflow are different airflows, and wherein the first period of time is different than the second period of time.
 8. The system of claim 6, wherein the PCM has a liquid to solid phase transition that occurs below a freezing temperature of water.
 9. The system of claim 8, wherein the PCM has a solid to liquid phase transition that occurs at a temperature below a freezing temperature of water.
 10. The system of claim 2, wherein the facility is a walk in freezer, a walk in refrigerator, a room of a building, a cargo container, a shipping container, a refrigerated food transport vehicle, a trailer, a trailer of a tractor unit, a ship, an airplane, or a rail car.
 11. The system of claim 2, further comprising a sensor to measure an ambient temperature of the facility.
 12. The system of claim 2, further comprising a sensor to measure a temperature of a good disposed within the facility.
 13. The system of claim 1, further comprising a sensor to measure a temperature of the PCM module or the phase change material disposed within a PCM module.
 14. The system of claim I, wherein the controller is further configured to: send a command to the chilled air generation system during the second period of time that activates the chilled air generation system that generates the chilled airflow; activate a reversible fan module of the forced air convection system in a first direction during the second period of time; send a second command to the chilled air generation system that deactivates the chilled air generation system during the first period of time; and activate the reversible fan module of the forced air convection system in a second direction during the first period of time.
 15. The system of claim 14, wherein the controller is configured to determine when to activate and deactivate the chilled air generation system based on a cost of electricity, wherein the cost of electricity during the second period of time is less than a cost of electricity during the first period of time.
 16. The system of claim 15, wherein the controller is configured to determine when to activate and deactivate the chilled air generation system based on an availability of electricity from a renewable power source, wherein the electricity from the renewable power source is available during the second period of time.
 17. The system of claim 14, further comprising a renewable energy source configured to supply power to the chilled air generation system and the forced air convection system during the second period of time.
 18. The system of claim 17, further comprising an on-demand energy source configured to supply power to the forced air convection system during the first period of time.
 19. The system of claim 17, further comprising a battery backup configured to supply power to the forced air convection system during the first period of time.
 20. The system of claim 14, wherein power is not available from an on-demand source during the first period.
 21. The system of claim 17, wherein power is available from an on-demand source during the second period.
 22. A system, comprising: a facility having an internal area; a forced air convection system configured to generate a convective airflow within the internal area of the facility: a chilled air generation system for periodically supplying a chilled airflow to the internal area of the facility; one or more phase change material (PCM) modules, each comprising a phase change material, wherein the PCM module(s) is(are) configured to exchange heat with air in the internal area; and a controller configured to determine: a first time period or periods during which to operate the forced air convection system; and a second time period or periods during which to operate the chilled air generation system; wherein the controller is configured to determine the respective time periods based on: one or more of a temperature of the air within the internal area of the facility, a temperature of a good stored within the facility, or a temperature of the phase change material or the PCM modules; and a cost and/or availability of electricity from a power supply.
 23. The system of claim 22, wherein the power supply comprises one or more of an on-demand power source, a renewable power source, or a battery backup.
 24. The system of claim 22, wherein the chilled air generation system is configured to provide chilled air at a temperature lower than a phase transition temperature of the phase change material (PCM), wherein: the PCM has a liquid to solid phase transition temperature or temperature range such that heat exchange between the chilled airflow and the PCM module causes a portion of the phase change material of the PCM module to undergo a liquid to solid phase transition; and the PCM has a solid to liquid phase transition temperature or temperature range such that, as the temperature within the facility increases, heat exchange between the convective airflow and the PCM module causes a portion of the phase change material of the PCM module to undergo a solid to liquid phase transition, thereby regulating a temperature of the air within the facility.
 25. The system of claim 22, wherein the controller is configured to operate the chilled air generation system: during periods of low relative cost of electricity from an on-demand power supply; or during periods when power is available from a renewable power source.
 26. The system of claim 25, wherein the controller is configured to operate the forced air convection system and regulate temperature within the facility via heat exchange between the air and the PCM modules: during periods of high relative cost of electricity from an on-demand power supply; or during periods when power is not available from a renewable power source; or during periods when power is available from a battery backup.
 27. The system of claim 26, wherein the controller is further configured to activate the forced air convection system at a first temperature threshold and to activate the chilled air generation system at a second temperature threshold.
 28. The system of claim 27, wherein the controller is configured to: send a command to the chilled air generation system during the second time period that activates the chilled air generation system that generates the chilled airflow; activate a reversible fan module of the forced air convection system in a first direction during the second time period; send a second command to the chilled air generation system that deactivates the chilled air generation system during the first time period; and activate the reversible fan module of the forced air convection system in a second direction during the first time period. 